Atenolol and drinking?

I am on a 25mg dose a day of this drug, and I've been on it for over a year now. I still get a little drowsy and some dizziness, but I was wondering if anyone knew if I could have the odd drink while taking it? I couldn't find a straight answer online. I am on Atenolol for a unsteady heart rate (would go from 50 to 140 in a 24 hour period).
Help?